Hydrogen has many uses including the production of ammonia, ethanol, and aniline; hydrocracking, hydroforming, and hydrofining of petroleum; hydrogenation of vegetable oils; hydrogenolysis of coal; reducing agent for organic synthesis and metallic ores; reducing atmosphere to prevent oxidation; as oxyhydrogen flame for high temperatures; atomic-hydrogen welding; instrument-carrying balloons; producing hydrogen chloride and hydrogen bromide; production of high-purity metals; fuel for nuclear rocket engines for hypersonic transport; and cryogenic research.
Hydrogen can also be utilized as a fuel, for example, rockets. It can further be utilized in fuel cells to generate electricity that can drive automobiles. Another use is as a direct transportation fuel for modified internal combustion engines.
Hydrogen currently is derived from many sources including (1) reaction of steam with natural gas (steam reforming) and subsequent purification; (2) partial oxidation of hydrocarbons to carbon monoxide and interaction of carbon monoxide and steam; (3) gasification of coal; (4) dissociation of ammonia; (5) thermal or catalytic decomposition of hydrocarbon gases; (6) catalytic reforming of naphtha; (7) reaction of iron and steam; (8) catalytic reaction of methanol and steam; and (9) electrolysis of water. Many of these processes require the use of a catalyst and require separate production plants to produce hydrogen.